


Baby Weight: Mommathyst

by MasterArchfiend



Series: Baby Weight Collection [5]
Category: Steven Universe (Cartoon)
Genre: F/F, F/M, Fluff, Gemlings, Parenthood, Pregnancy, Smut, Weight Gain
Language: English
Status: Completed
Published: 2020-10-25
Updated: 2020-10-26
Packaged: 2021-03-09 02:20:35
Rating: Mature
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 2
Words: 2,767
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/27186476
Author URL: https://archiveofourown.org/users/MasterArchfiend/pseuds/MasterArchfiend
Summary: The next adventures in the Baby Weight AU is here with Amethyst and Pearl fulfilling their daughter's wish for a baby sister.
Relationships: Amethyst/Pearl (Steven Universe), Blue Diamond's Pearl/Yellow Diamond's Pearl (Steven Universe), Connie Maheswaran/Steven Universe, Lapis Lazuli/Peridot (Steven Universe)
Series: Baby Weight Collection [5]
Series URL: https://archiveofourown.org/series/1680229
Comments: 1
Kudos: 9





	1. The easy part

**Author's Note:**

> As you noticed, this is two chapters. Why? Two major reasons.
> 
> 1) My phone is almost dead so I don't want to wait to write the rest without posting something. 
> 
> 2) Winter is rough on my hands, the cold drying them out until they crack and bleed even with lotion so my hands hurt from typing so fast.

Everyone was gathered around the picnic table, the kids all sitting next to each other as they waited for the cake. Pierre constantly readjusting her hat, Green refusing to let go of her stuffed racoon, young Rosey sitting on her father's lap and of course Percy sitting next to her best friend and gem of honor. AJ was giddy, bouncing in her seat as her Mommathyst brought out the cake.

Candles lit, Pearl insisted they sing the Birthday song. With a harmonious "Anastasia Josephine" from all present, the little quartz blew out the candles, but not without saying her wish just loud enough for her mothers to hear. "I wish for a baby sista."

After cake came presents and supervised mayhem as Anastasia insisted on hide and go seek with teams. Pearl and Amethyst watching adamantly, but clearly distracted. "You heard her too?" Amethyst asked, already aware of the answer. "Do you?" Pearl didn't even need to ask the full question. At this point most of their one on one conversations boiled down to simple exchanges since they learned how to express most things without the need for words. 

The shorter gem fiddled with her hair, having recently reformed with it in a permanent pony tail and only a small phanny pack for emergency supplies being the only alterations. "Can it be me this time?" 

Pearl almost scoffed. "Of course. I know that you wanted to be the one the first time so it is only fair that you carry our second child."

"What's this about a second kid?" Steven appeared, startling them both. Little Rosey clearly trying to reach her mom who was busy with their diaper bag and shoving her father's cheek in the process. 

Amethyst laughed. "We overheard AJ's wish and she wants a baby sister."

The young man (by gem standards anyway) nodded with his usual sagely air. It was good to see him being goofy again after finding just the balance between that and seriousness. Rosey, having seemingly realized that her father was not going to hand her over to mother, started whining which summoned Connie at a speed only a parent could move. "Is she hungry?" 

The conversation continued with a change of topic and slow rotation of parents as some needed breaks from play time. Pearl and Amethyst silently agreeing to wait to let everyone else know and actively threatening Steven's hair should he tell.

After the party ended and see you's were exchanged, Peridot having to actively carry Percy who had attempted to play longer with AJ and said Birthday gem cleaned up and happily snoring; it was time to try.

-_-_-_-_-_-_-_-_-_-_-_-_-_-

And try. And try. And try for the next month until one evening Pearl and Amethyst lay next to each other staring at the ceiling. "This was not this hard last time. What are we doing wrong?" The purple gem was frazzled. Peridot has assured her that she could easily get pregnant with a gemling back when they planning AJ. What was the problem?

Sure it took a bit of maneuvering to get Pearl's gut out of the way so Amethyst could ride her, but that didn't keep them from doing it. Was there something else?

Pearl was looking over all her parental research, face scrunched up in that cute, focused way that made the quartz feel like she was admiring a piece of art instead of reality. It was hard to not admire her beauty, even after all this time. 

Suddenly the pale gem turned, almost smacking the purple gem with her naked breasts. "I'm sorry love. Are you alright?"

"You know something is wrong if I am not okay with wife boob to my face."

"Always so crude."

"You curse like crazy during. It's practically a rap album."

Pearl shoved a piece of paper into Amethyst's face. "It's a funny coincidence that you mention music because I found something in my notes that I forgot!"

The purple gem examined the paper. It was a list of songs that she knew. What in the- "The baby maker playlist! I can't believe we forgot that!"

"Well the purpose was to make it less stressful and I guess we just assumed that we didn't need it. I don't see why we needed it in the first place, but it couldn't hurt."

Amethyst pulled up the list and got comfy. "Let's rock."

With a roll to her eyes, Pearl moved on top of her wife, pale gut resting like a fleshy blanket and proceeded to gently kiss the chubby cheeks down her jaw line to her gem, giving it a quick lick which made Amethyst gasp. 

"I don't need teasing P."

"Oh? You mean you want me to fuck you like a slut~"

Thank the stars AJ was spending the night over with the Lazulis, even if it meant Peridot ranting about the kid being too handsy with her daughter and Lapis reminding her of their ages. 

Before that train of thought could continue, Amethyst felt two gentle, yet strong hands grip her breasts, fingers squeezing her nipples. Suddenly she felt it. Pearl knew her well enough to get the size, shape and texture down to the point that just the member's presence made her folds wet with longing. 

Grabbing the headboard, the quartz braced herself as Pearl thrusted in, not to get a good angle, but the keep her head from smacking into it. Her wife may not be the slevette dancer anymore, but even at thrice, almost quadruple her default weight, the pale gem was still just that, a gem. One who knew how hard to thrust and how fast to make Amethyst see stars. 

The pounding against her inner walls, the music playing in the background and Pearl's plethora of dirty talk left Amethyst in ecstasy. Feeling herself close, Pearl adjusted her position without braking pace, lifting the purple gem's legs up as she pounded down, the weight notably making the bed groan if Amethyst could hear it over her own. 

Screaming her name, the purple gem felt Pearl unleash a fresh load and felt warmer than usual. 

-_-_-_-_-_-_-_-_-_-_-_

It was a week later that Amethyst stared at the test, wanting to scream at it to hurry up or else she'd drown it next time, but AJ was in the living room, Garnet put a cape on Cat Steven. 

Pearl walked in, hair covered in cat food and surprised to see her wife. "I thought that we already tested?"

"Yeah, but I heard that the brand we used was recalled for not working. Apparently they mixed the weed testers with the baby testers. Figured it was worth a try."

Both look to the test and froze. Positive. Not even hesitating, Amethyst took a second one and both stared with bated breath. Positive.

Their resounding scream startled Garnet and AJ, but Cat Steven simply played with her cape. They ran to see Pearl twirling Amethyst around in joy, the shorter gem starting to pick out the cat food to eat. 

"Amethyst!"

"Wha? I neesh the food!"

AJ walked up to her mom's looking very confused. "It's lunch time?" 

Both looked to each other before wrapping AJ into a hug. Pearl answering. "Not yet, but Mommathyst is going to need to eat more often."

The toddler looked between them. "Why? She grown."

"I'm grown, but your sister isn't."

Anastasia's eyes widened, stars appearing. "Sista! Where?!"

Amethyst placed a hand to her stomach and the child screamed. "You ate her?!"

Pearl quickly grabbed the child into another hug. "No princess. That's just how babies work. They start in a mommy's stomach until they get big enough and then the mommy goes to a doctor to help get the baby out. Think of it like those toys of yours that grow in water. Right now your sister has to stay inside Mommathyst's water until she is big enough to not need it."

The little quartz made a pout much akin to her mother as her own gears turned before talking straight to Amethyst's stomach. "Stay outta the oven so you don't need to go back in, 'kay! I'm gonna be the best sista for you ever!"


	2. The actual weight gain

**Summary for the Chapter:**

> Now to the kinky part, some drama and fluff.

Amethyst was surprised how all their friends and family brought food as congratulations, except Lapis who seemed to be the only one who brought some new baby toys in case the newborn didn't like the hand-me-downs from AJ. Seriously, even Garnet got her a gift card for Fish Stew Pizza. The kids were a bit more practical by bringing pictures they drew for the nursery Pearl was already planning.

Not to say the food wasn't appreciated. Maybe it was because she already had a love for eating or perhaps it was due to her shorter stature, but the purple gem seemed to start eating with gusto sooner than her wife. She also seemed to nap more after each meal.

The quartz was already a bit husky, but as her stomach rounded out, thighs thickened and breasts filled out her shirt, she was definitely in fat territory. Nothing quite drove this home more than one morning in particular. 

Amethyst grunted as she pulled up her shorts, the fabric groaning as it went, before reaching a suitable height only for the gem to realize something. "Babe? I...uh..can't see the button on my shorts." Her stomach was definitely hard with a baby bump, but there was enough fat to sink just low enough to obscure her view of her front.

Pearl came in with a playful smirk. "Oh? Perhaps it's time to switch to the basketball shorts."

"Hah hah. You didn't need help with your pants so soon."

The pale gem ran her hands over the purple gem's stomach, pausing for a moment. "Let's take you to see Peridot. I'll grab your black shorts."

-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-

Amethyst wasn't sure why, but for some reason it felt odd to be sitting in her underwear as her friend placed some weird jelly on her stomach, something about it helping the scanners, while Peridot hummed some nursery rhymes. 

Said gem noticed the difference in the quartz's demeanour. "Feeling shy or something Big A? You've been naked in my home more than I have."

The purple gem rolled her eyes. "Modeling for Lapis isn't the same as finding out why I am growing so fast."

The green gem nodded. "Well I already have a guess, but let's get some confirmation first."

A few screen taps and a robonoid scanning with a weird hum led to a bing. Peridot looked at the screen and laughed. "Of course I was right! Congrats Amethyst! You've got two healthy-"

"TWO?!"

"Yes. Two baby-"

"I'm gonna blow up like a blimp!"

"I had twins and didn't get that bi-"

"You got too fat to get out of bed near the end! Oh stars! How am I gonna help with AJ? My princess!"

Peridot took a spray bottle from her drawer and used it on Amethyst's face, enticing a "What the hell?!"

"You need to calm down. You have Pearl, Garnet and the rest of us to help when you get too big."

"But I just can't sit for days P-dot. You watching t.v. for days on end is normal, but I can't sit still for that long."

"For the record I don't watch to that extreme anymore and you just need to remain active until you get big enough."

"Active? I have to wear baggy shorts now and I'm not done growing. It's not like I can parade around in my undies."

"Why not?"

"Do you go around barely dressed with your kids home?"

"Do the bikinis I wear to the beach count?"

-_-_-_-_-_-_-_-_-__-_-_-_-_-_-

Back home Pearl was given the news. "Twins?! Twins?! Twin what?!"

Amethyst shrugged her shoulders. "I kinda kept interrupting her to freak out about my impending hugeness. Does it really matter? We didn't know what AJ was going to be so why not let them be a surprise too?"

The pale gem went behind her wife to wrap her arms around her. "I suppose. When should we tell Anastasia?"

"Tell me what?"

The little quartz came out of the bathroom into the living room, hands still a bit wet after washing them.

The two parents looked at each other out of the corner of their eyes before nodding together.

"Hey little dude. How do you feel like having two baby sisters?"

The gemling paused, face schrunching up. "May I have two?"

Pearl laughed. "Yes you may. You're going to have two baby sisters. Mommathyst is having twins like Percy and Pierre."

The little gem rushed forward to hug her mothers. "Best mommas!"

AJ was clearly ecstatic. 

-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-

Amethyst was not. It didn't take long before her stomach became too big for her to pull her shorts up and Pearl had become a bit busy with AJ getting ready for school. 

"Why can't we homeschool her? We did with Steven and he's one of the smartest guys on the planet."

"Steven was born in a time of tension with corrupted gems and Homeworld being a threat in addition to being a hybrid with no place to legally attend. Thankfully the local schools have opened a well designed program for gemlings so they can get all the benefits of a proper school experience."

"What about bullies? Huh? Don't we gotta protect her from them?"

Pearl crossed her arms. "I know that you are feeling needy right now, but don't use our daughter to give me reasons to be there just to put on your shorts."

"Am I really freaking out that much?"

Amethyst had been given her answer when Pearl took her to shop for "Maternity dresses?!"

The pale gem smiled. "They are designed so you can put them on without my help. This way I can get AJ ready for school while you get dressed."

The purple gem looked at the various fabrics, pouting. "Why can't Garnet?" 

Pearl was already picking some dresses out, opting for whites and blacks, as she replied. "Garnet is already doing the cooking and helping out at Little Homeschool. I give you enough attention before bed as it is."

The shorter gem looked down, chins squishing into her breasts. She had been quite needy lately and that extended to Pearl being handsy for a good chunk of the night. 

-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-

Amethyst was surprised at how well the dresses fit. They accentuated the curve of her stomach, the wideness of her ass and kept her large breasts modestly covered. It kept her active, which was mostly just waddling around to do minor things like grab things from the counter or help AJ with her first homework (somewhat regretting giving the child such a long name as she struggled to write it out).

She had shown her friends her new outfits and got a kick out of how Jasper immediately told Bismuth they were going shopping on the way home. Lapis even requesting to sketch her in one. 

It was a bit embarrassing at first as she wasn't one for dresses, but it beat needing someone having to pull pants up for her since her belly didn't give way.

Thankfully that issue soon became resolved with her first contraction while drying dishes.

-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-

She had no idea how Pearl or Peridot handled the pain, be it from the birth or from screaming so loud that she would've been worried of AJ hearing her from the Lazulis', but it was worth it.

Two beautiful little pearls. 

One with hair wispy and pale grey with a slightly darker body, looking almost like smoke. Eyes like lightning bugs. Her gem small and round on her forehead. Wisp was such a calm one even when AJ got very close to her face.

The other was a dark red with bright pink hair and the richest green eyes one would expect from an emerald. Little Persephone had her gem located on the back of head, near the base of where her skull would be if she were human. Unlike her quite twin, she was rather loud, but instead of crying she was all giggles, being absolutely delighted when AJ said hi for the first time to her.

-_-_-_-_-_-_-_-_-_-_-_-_-_-_-

Amethyst placed her hands underneath her stomach, lifting it just long enough to button her shorts. "Ugh. Should I even bother working this off?"

Pearl looked over and smirked. "You'd have to give up bacon for awhile."

The quartz gasped. "You'd deprive a mother of bacon?"

The taller gem laughed. "Of course not! I'd be eating your share~"

"Mom! Mommathyst! Wisp and Persi are up!"

**Notes for the Chapter:**

> I'll be back to requested drabbles in a bit. I just needed to get this done for myself, a friend and all of you.


End file.
